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February 03, 2005

Highly improbable

When I was an undergraduate at USC, I almost failed Probability. I recall homework assignments that simply stumped me: I knew neither how to solve the problems, nor even how to interpret tutorials that claimed to explain similar problems. It affected me financially: my apartment security deposit was hit for repairs to the wall, after I flung the Probability book one night in frustration.

I am convinced that the rest of my life will be spent re-learning (slowly) the things I failed to learn the first time when they were taught to me in high school and college. Math, science, history, philosophy, literature... In small ways I've revisited each of these with fresh interest. Why couldn't I have just gotten it them first time around?

So, too it is with probability. Specifically, Bayesian nets. Bayesian nets are a fascinating melding of computer science and mathematics. They are (in my limited understanding thusfar) directed acyclic graphs, where nodes represent random variables, and edges represent conditional probabilities. Inferring joint probabilities from them makes tons of sense. Updating them is harder. Designing them from scratch is a bitch.

But I'm learning. I've found plenty of sites on Bayesian nets. See http://del.icio.us/ehgradman/bayes for a collection of helpful resources.

January 25, 2005

New Job in a Downtown

Started a new job today, with an advertising company in Downtown Los Angeles. I've always wanted to work in downtown. I was overwhelmed by the number of people on the street during lunch time. I've seldom visited downtown during daylight hours; I tend to sneak in under cover of darkness. I took the subway to work, and I'm sitting in the station where I'll catch a subway train home. I never imagined I would ever not drive to work. I've never known anyone in Los Angeles who customarily took this puny little subway system to work. Friends from around the country who I tell of this development generally react with confusion: "Los Angeles has a subway?"

Downtown has a very different feel to it from West Hollywood where I used to work. There are so many homeless people in downtown, crouched beside buildings and in crowded thoroughfares. Living near USC seared most of the conscious sympathy from me. But deep down, I feel so sad that so many people have to live outdoors. The weather's nice. I'm also jaded by having my car broken into a number of times, and friends held up at knifepoint (nobody can afford guns in these neighborhoods). In West Hollywood, homeless are more likely to beg you to read their script.

I'm nearing my subway exit. Signing off.

January 09, 2005

My cat is a menace

As a new cat owner, I am struck by my cat's uncanny ability to identify my precise point of focus and sit on it. If its a book, he will identify the very paragraph I'm reading and obscure it with his tail. If I have my computer in my lap as I'm doing now, he will find the most damaging keys (key combinations!) and depress them with his grubby little paws. He has found features of MacOS X I was unaware of and have been unable to duplicate; however this behavior must stop. Five minutes ago he paused on the power button and managed to turn my laptop off before I could dislodge him. My cat instruction manual advises me to use a spray bottle mist to discourage my cat of bad behaviors. This solution is clearly ill advised where my computer is concerned.

I need a "Cat Alert" macro key on my keyboard. When I press it (F12?) it locks the keyboard, much like the lock on a cellphone keypad. A simple key combination (shift-F12?) unlocks it again. An applescript perhaps, triggered by an F-key macro? I don't presume to match my cat's... um... cat-like reflexes. But when I do have some warning of an impending pounce I want to preserve my work, and my cat's affection.

I call on thee, oh great LazyWeb! Is there an answer to my plight?


(Look! You can see him reaching for the power button!)

January 06, 2005

Oh, has it come to this?

Having lost my Sony Ericsson T610 (piece of crap), I am the new owner of a Samsung C225. It cost me $30 and it has perfect signal strength in my apartment, which is worth far more to me than a camera. It has no bluetooth, which I can deal with for a short time. This phone serves only to tide me over until I can afford a real geek phone with a real operating system.

But I'm discovering that in some ways, you get what you pay for. Every ringtone shipped in this phone's firmware is some poor MIDI rendition of a song. Or the sounds of space invaders landing on your lawn. Or a piano impacting an elephant.

It cost me $1.50 online from T-Mobile just now to download a ringtone to make my telephone sound like, well, a telephone!

Next, I expect they'll start charging me for parts of speech when I talk.

December 09, 2004

400 channels and nothing on

I'm lying in my old bedroom at my parents' house, having decided to crash here after a long day at work. I can hear the sound of television in my parents' room. Its an unfamiliar sound... I don't own a television. I find television incredibly distracting; so much so that when I decide to sit down and watch a movie, I have to devote my whole attention to that activity.

Television's components are distracting. In bars and restaurants I intentionally sit facing away from television sets. If I can see the picture and not hear the sound my brain is drawn to try to reconstruct what's going on. And if I can both see and hear, I'll be unwittingly sucked in by whatever is on, no matter how asinine. I have no acquired immunity from television and television advertising. I don't seem to have the same calluses over my eyes and ears that allow people to have conversations while berated at high volume to buy a discounted mattress.

So now I can't fall asleep, because I can hear the television in the other room. Or maybe because I can tell my parents are watching South Park. If you know my parents, you realize why this is so funny. If you don't know my parents, then visualize the people in the world least likely to watch South Park. That's my parents. My Dad got a TiVo for Hanukkah. I think this gift (of course, purchased at Costco) was residing here temporarily and was tagged as a gift to a family friend. But it was intercepted by my Dad. And now my parents, who don't watch television, are watching South Park. Can someone explain the psychological power of the TiVo, that makes my parents record for later viewing programs they would never have watched in the first place?

December 03, 2004

REST architecture

I'm helping rearchitect a system that uses a proto-REST API on its backend. Unfortunately, everything is POSTed to one URL which uses PHP includes to import necessary functionality...

December 01, 2004

Deleting duplicated rows in SQL

I came across the problem of duplicate keys in a PostgreSQL database today. There was (unfortunately) no UNIQUE constraint on the email column where there were duplicates. I wanted to manually effect uniqueness on the email column. The solution took awhile, and strained my limited knowledge of SQL...

DELETE FROM table WHERE uid NOT IN
(SELECT min(uid) FROM table GROUP BY email);

Predictably, this took a long time to execute. Is there a more efficient (or graceful) way of doing this? There's no index on the nested SELECT, so this method requires a linear search through the results of the nested SELECT for each row of the table.

November 29, 2004

My first computer

My very first computer was a NEC PC-6001A. It was purchased for me when I was three years old (1983), by forward-thinking parents who were learning to use their own Columbia computer for word-processing, etc. They were generally thwarted in their endeavor by my loud insistence that I be allowed to play Space Invaders.

For some reason, I never bothered to research this important part of my childhood. I discovered it recently only by accident at the Obsolete Computer Museum.

From the page:

This is a picture of a NEC PC-6001A I bought at a local flea market (for less than $10) about four years ago. This computer was on the market around 1981-2 or so, but was never distributed widely in the U.S.

The computer as shown has 8K of ram, plus built in Microsoft BASIC. I don't think it has dot-addressable graphics, but it does have color TV output and a set of line drawing characters (plus a small selection of other special characters, accessed by pressing the "ALT CHAR" key on the keyboard). It also has a three-voice sound generator (similar to TI-99/4A, MSX, etc.) and a built-in speaker, accessible from BASIC.

...

This computer was marketed as the "NEC Trek" computer. In spring 1994 [1984, actually] in the Los Angeles area, it was sold by The Federated Group, as a bundle deal: Computer, joysticks, thermal printer, cassette recorder, monitor, disk drive, "expander," and some other goodies for $350. Federated also sold some cartridge games and other stuff.

I definitely recall playing "Canyon Climber" on this computer. It came on a solid cartridge like the one pictured (I remember the cartridges being much bigger... probably because I was so much smaller).

October 11, 2004

Cobwebs, begone

The cobwebs in this weblog are starting to resemble the ones in my apartment. Were it only that a simple robots.txt file would rid my place of those pests. They're fast spiders, and smart. They can see an airborne shoe half a room away.

I'm moving out of this place soon. But there are strata of cleanup tasks to be performed before I can begin to pack. The post- Burningman chaos overlays my pre- Burningman mess which overlays the default state of disorder. Then there's all the stuff. I've been living out of the same duffel bag for the last two months. I have truly found the bare essentials of what I need to survive. The only problem is that if I happen to mislay anything essential, this useless crap clogging my apartment swallows it up. The Goodwill will be getting a big donation from me soon. Let them trip over it.

I may have found a new place to live. Vicki and I found an amazing apartment in Koreatown. Now we just have to sort out my job situation, her moving back to Los Angeles from New Orleans, and how I'm going to keep the spiders from hitching a ride in my packed boxes.

We got engaged. Yes, engaged to be married. My delight is inexpressible in text. You'll have to ask me about it in person. Me jumping up and down and smiling ear to ear is essential for properly conveying that story. If I haven't eaten recently I might even do a backflip. Its that cool.

September 16, 2004

Back from adventuring

With great reluctance, I opened my laptop to confront the three week build-up of email and feeds. The keyboard felt strange under my fingers. The screen strained my eyes. I gave up.

I tried again. Amazing how email and RSS feeds which sap my time and consume my attention are so phenomenally boring after an adventure. I'm done talking about them.

Burningman

How can I describe Burningman? If you've been, you understand the problem. If you haven't, no explanation I provide will illuminate things. Go.

Most people arrive at Burningman for the first time completely unprepared. One's first Burningman experience is half spent biking from installation to installation, camp to camp, wild-eyed, rushed, and overwhelmed. The other half is spent begging for things you forgot. Enough food. Enough water. In contrast, I spent my first Burningman among experienced friends who kept me alive. As part of the Mutaytor I worked my ass off on our projects. Most people grow increasingly more prepared with each subsequent Burningman, and work increasingly hard on projects leaving less time to screw around. In contrast, I have screwed off increasingly more. This was my third Burningman, and I was a complete bum. I slept well, I ate well. And if you didn't come visit me in camp, I didn't go visit you. It was wonderful.

Vicki and I were inseperable, and she took to the place better than I did my first time. In fact, the reason I was so comfortable in camp, ate real meals, and showered regularly is because she kept the place organized, helped prepare food, and told me when I smell. It was not because I was necessarily better prepared than usual.

Most people either hate Burningman and resolve never to return, or love it and resolve to return forever. She wants to go back with me. That's a good sign.

Three sets of friends got engaged on the playa: Buck & Roo, Atom & Athena, and Spaceman & Karen. One set got married: Little Bit & Brian. Wow.

Best Art
The 9x9x9 spinny cube thing
Best Art Car
The Shower Car
Most memorable experience
Rocking out 10,000 (official count) people at the burn night show.

more about this adventure in future posts...

August 26, 2004

Two excellent pieces of news

  1. Tomorrow at this time, I will be on the playa.
  2. I got a job.

Life is sweet. More on these topics as they develop.

August 25, 2004

Burningman prep pt. 2

Checklists, mental and scrawled on scraps of paper, were consolidated and the items checked off. Boxes were shut, sealed, labeled, and stacked. Gradually, the floor of my living room was revealed. Then in the span of an hour, my apartment gained some semblance of order. I'm not done yet—there are things still to be collected, pipe to be cut, some final items to pick up. But for everything, there's now a place.

The time-lapse photography of my camp setup is playing out in my mind. Having so triumphantly packed, I'm now imagining gleefully tearing it apart. Items newly purchased and items bearing evidence of past camping trips will litter my tiny patch of playa, and gradually coalesce into our home for twelve days.

I'm almost there... Tomorrow, the truck packening begins. Hopefully we'll only have to do it once this year.

August 21, 2004

Amidrine - Acetaminophen/isometheptine/dichlorophenazone (oral)

Acetaminophen/isometheptine/dichlorophenazone
The medicines in my prescription migrane pills, which I am now consuming in the prescribed amount.
(oral)
A helpful hint on where to put said pills.
IMPORTANT NOTE: THE FOLLOWING INFORMATION IS INTENDED TO SUPPLEMENT, NOT SUBSTITUTE FOR, THE EXPERTISE AND JUDGMENT OF YOUR PHYSICIAN, PHARMACIST, OR OTHER HEALTHCARE PROFESSIONAL
Uses: This medication is used to relieve migraine and tension headaches

I suffer from migraine headaches. I can tell within a few hours of waking up whether I'll be incapacitated with pain by the evening. And if I go to bed with a migraine, I'll wake up with an even worse migraine. They're my own damned fault—if I don't eat breakfast in a timely manner I'll get a headache. Breakfast can be substituted with a back-breaking toil in most cases. It's something to do with blood-flow, I think.

That said, a backbreaking toil is also o a cure for a migraine. So is good conversation, and often sex. All three however have an "activation energy" which is usually unattainable when I'm squinting my eyes in pain and trying to stay very, very still.

I'm suffering from a migraine headache right now. The acetaminophen in this medication is turning my liver to swiss cheese, but my brain continues to hammer its way through my left temple. I'm sending in reinforcements, PRECAUTIONS: be damned. Livers grow back, brain cells don't.

According to the helpful table included with this prescription, a migraine only affects one side of the head, whereas a tension headache can affect one or both sides of the head. The included table reveals that a migraine is in all other respects a "really bad" tension headache.

According to the Wikipedia (which is a substitute for the expertise of a healthcare professional) the word migraine has its roots in Ancient Greek: hemi+krania (half-head). That's reassuring, somehow. The ancient Greeks too, in all their brilliance, were brought to their knees by malfunctioning cranial blood-vessels. The togas made sex a more viable curative I'm sure, but they definitely didn't have Amidrine.

I think its a placebo. Wikipedia lists a whole host of migraine medications and Amidrine isn't among them. Wikipedia also lists some "traditional" cures, including acupuncture and the extracts of various plants. But the Ancient Greeks didn't have any fancy modern medication, and they managed to survive! Er, uh oh...

No, further research does not definitively tie the fall of Ancient Greece to migraine headaches. I had to make sure. This migraine may be the end of me though. I'm going to try a traditional cure of my own—alcohol. Livers grow back, brain cells don't. Here's to Ancient Greece!

August 17, 2004

I can smell the playa dust

If you've ever smelled playa dust, you know how I feel. Well, perhaps "smell" is the wrong word. Have you sanded the paint off a house? Your nose is definitely involved, but its not exactly an olfactory thing. Anyway, I'm getting that fullness of the sinuses that can only mean its time to return to Burningman.

I have a dream every so often: I've got about 15 minutes until my ride to Burningman leaves, and I haven't started packing. This is an evolution of that older dream where I'm about to take the final exam for a class that I stopped attending after the first week. Sometimes its a curse to have your dreams come true: I have four days to get my things together, and staring at the empty space I've cleared to stage my gear isn't exactly spurring me into action.

This is my third year on the playa. By all rights I should have this process down. And indeed, I'm counting on my prior experience in surviving Burningman to bear me through what portends to be a rushed, haphazard packing. I have what you might call a low standard of living out there. I eat out of cans and lug around my own body-weight in caked playa dust. I sleep in a tent that either retains or releases heat, whichever is least comfortable at the moment. But in the past I've only had to keep myself alive. This year I'm bringing provisions for myself and for my girlfriend Vicki, a Burningman virgin. And so, because I love her, and perhaps out of a certain degree of embarrassment, I'm taking great pains to make our camp comfortable and luxurious. I really think I'll appreciate luxury more when I can share it with someone.

I have four days. And that empty space where I'm staging my Burningman supplies isn't filling up on its own. Panic is rising in my stomach like a dust-storm.

No, that's not true. I went to Pep-Boys today and bought a 10'x20' car-port. As playa accomodations go, its suitable for a family of six. If I somehow managed to forget all my other belongings at home, I know that I would at least have a warm, insulated enclosure in which to play jai-alai.

I won't starve, and I won't freeze, and neither will Vicki. But the prospect of making this a miserable experience due to inattention to detail on my part is chilling nonetheless.

But I'm pushing that attitude firmly out of my mind as I conclude this post. In a few short days I'm going home. I'm going to be surrounded by the friends I love, sharing Burningman with the woman I love, and helping build the city I love.

And I'm going to get covered in playa dust.

The man burns in 16 days

August 13, 2004

I've been outsourced


From: "Monster Jobs"
To: eric@gradman.com
Subject: Qualified Job Opportunity
Date: Tue, 17 Aug 2004 02:38:35 -0500

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&jsdjobsearch.monster.com&hdcompany.monster.com&adjobsearch.monster.co.in

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(see what they came up with after the jump...)
(more...)

SIGGRAPH wrapup

The frequency with which I check my email is a good indicator of how much fun I'm having. Seldom does the world muster enough distraction to compel me to ignore my email and my RSS reader. Burningman does it handily. This week, so did SIGGRAPH.

I arrived, a guest of the Guerilla Studio/Cyber-Fashion Show, completely unprepared for the forthcoming sensory and intellectual onslaught. My first impression of the event was formed in the Guerilla Studio, a hodgepodge of fully equipped computers, laser scanners, rapid prototyping machines, motion capture systems, and printers. There was a "dot-matrix" printer that used sand as its ink and and the floor as its canvas.

But I was taken by the creativity that pervaded the room. Individuals and groups were engrossed in marvelous activities: constructing futuristic garb for the cyber-fashion show; operating a printer that prints on human fingernails; tweaking 3D models for instant "incarnation" in plastic, fine-tuning a dopper-effect computer simulation. People were sitting in front of computer monitors or slaving over soldering irons, but they were operating them as paintbrushes and pianos. What's more, this art defied any convention. There were so many people in this room helping to blur the lines between sound and light, dance and inverse kinematics, physical and digital.

In reflection, I find it strange that even as a technical person I find it easiest to employ metaphors to relate to how I felt when I encountered this environment. I'd like to think that its because I related to this event as an artist, then as a techie. But then again, when the digital world is your canvas, is there any difference? It was inspiring to see the mode of art that I want to create, and to feel I had something in common with its creators. It was also incredibly humbling to discover I've been working in a relative vacuum, ignorant of so many incredible creations and tools.

I toured the Emerging Technology gallery at SIGGRAPH, and my mind was summarily blown. I was fortunate to have Athena Demos accompany me and drag me out by the hand when my attention-span hit rock bottom and I began stumbling from installation to installation, wide-eyed, staring at everything but absorbing nothing. I compare it to the feeling of arriving on the playa for the first time, confronted with a world so obviously full of possibility yet too vast to comprehend at once.

I smoked a cigarette and bought a book on Beginning OpenGL. I have since managed to render an icosahedron, though I think it looks a little lopsided.

Over the course of the convention I experimented with graphics and electronics and sound generation. I practiced my solder-fu to help fix costumes, and I even strutted down the cyber-fashion show runway wearing a vest equipped with an illuminated indication of the Homeland Security Alert Level. I passed out resumes and business cards. I donned an LED-studded costume and spun electro-luminescent meteors in the lobby. I cursed at my virtual icosahedron, many coffee-fueled late-night hours in the making, and definitely still lopsided.

Most importantly, I got to interact with some amazing, skilled, creative people. They proved that applying geekery to art is not a waste. I am inspired to create as I've never been before, and I've discovered a global community of geeks with whom to collaborate and share.

And perhaps I'll even get a job out of this. I'll try to write a more practical SIGGRAPH wrapup, one less encumbered by metaphors or my early-morning compulsion to be "eloquent."

August 06, 2004

InverseFunctionalProperties and distributed hash tables

This thread discusses the intuitive use of InverseFunctionalProperties to refer to objects expressed in RDF on the semantic web. What is an inverse functional property? It is a property (or attribute) of an object that uniquely identifies that object. A social security number is an InverseFunctionalProperty of a person that, when taken alone, uniquely identifies the person who possesses it.

It is valuable to refer to objects by inverse functional properties because it short-circuits the technical (and sociological) problem of assigning canonical URIs to objects, as is the current RDF practice. URIs are a hierarchical naming scheme based, somewhat unintuitively, on the domain name system. This scheme binds object names to an existing hierarchy, which serves a practical purpose at the moment: it combines the naming and the addressing schemes for referring to objects.

However, there's a mismatch here. DNS load balancers are an illustration of this mismatch. You request information from www.yahoo.com, but there isn't a single host called "www.yahoo.com" serving up that information. Your request is, in truth, a request for information from an abstract resource: yahoo. See this paper for a better treatment of this topic.

For InverseFunctionalProperties to serve as effective resource identifiers, there must be a distributed mechanism to associate properties with the resources themselves. Put differently, some abstraction layer must be built between the naming scheme that InverseFunctionalProperties provide, and the addressing scheme that URIs provide.

InverseFunctionalProperties exist in a flat namespace, bound only by the constraints of the ontologies that define them.

Consider a distributed hash table which provides a flat keyspace. InverseFunctionalProperties can comprisee part of that keyspace. Simply concatenate the ontology URI that describes the InverseFunctionalProperty with its value and write or read the key in the distributed hash table. The value written and read from the hashtable for such a key would be a resource URI for the InverseFunctionalProperty's inverse (optionally signed by its owner or by a third party).